This invention relates to a process for deforming hair. More particularly, the invention discloses processes and compositions for curling or straightening human hair employing monopersulfate oxidizing agents which do not substantially bleach melanin when employed under the conditions hereinafter disclosed.
Both hot and cold hair curling processes involve various heat or chemical treatments, or combinations thereof, to disrupt the keratin structure of the hair. Following this initial disruption, the hair is subjected to longitudinal stresses, for example, by winding on a mandrel, following which the keratin structure is substantially reestablished with the hair in the curled configuration. Curling processes employing heat and caustic solutions are known as "hot" processes, whereas those employing chemical compounds such as the thioglycolates are known as "cold" processes. Cold processes have come into general acceptance inasmuch as they can be utilized by relatively inexperienced operators in home permanents.
It is recognized in the art that hair which has been extensively bleached, i.e., subjected to oxidative conditions whereby the malanin is substantially destroyed, is relatively easy to curl or set in a more-or-less permanent configuration by simply moistening the hair and subjecting it to a longitudinal stress. Presumably, common hair bleaches disrupt chemical bonds in keratin fibers with a net effect similar to that when hair is contacted with a thioglycolate cold waving solution. Hair in which the keratin molecules are oxidatively disrupted is thereby rendered deformable and the hair can then either be curled or straightened, as desired. Of course, hair treated with the common hair bleaches, e.g., a basic solution of hydrogen peroxide, is not only more susceptible to curling but also has a different color due to the action of the bleach on the malanin color bodies in the hair. For this reason oxidative hair bleaches are not generally considered to be acceptable for curling hair inasmuch as the user must thereafter tint or dye the treated hair to reestablish the original hair color.
It has now been discovered that a certain class of oxidizing agents, the monopersulfates, can be applied to hair to oxidize the chemical bonds in keratin, thereby rendering the hair deformable without substantial bleaching of the natural hair color. It is surprising that the monopersulfates are capable of disrupting the keratin fibers without attendant bleaching, inasmuch as these compounds are well-known as bleaches for synthetic fibers. Presumably, the kinds of stains which can be bleached from fabrics and fibers are sufficiently different from the melanin coloration of the hair that the monopersulfates, while capable of bleaching such stains, have no substantial effect on malanin. In any event, it has now been found that monopersulfates can be applied to hair to cause sufficient disruption of the keratin fibers to allow the deformation of the hair by applying a longitudinal stress thereto, but without changing the natural hair color.
The use of per-salts, including persulfates and monopersulfates in the neutralizing solution of hair waving compositions is known in the art; see, for example, U.S. Pat. No. 3,583,408 and ELCHEM 1384 Catalog, DuPont. When employed as neutralizers, such per-salts are commonly used in the acid pH range following the thioglycolate treatment to reestablish the sulfur-sulfur bonds in the keratin fiber, whereas by the present process it has been discovered that monopersulfates can be employed to disrupt keratin bonds. U.S. Pat. No. 3,679,347 teaches the use of monopersulfates in hair dyeing processes, but does not suggest their use for deforming hair in the manner of this invention.
The concurrently filed application of J. A. Anderson, entitled "Hair Setting Process", Ser. No. 294,052, filed 10/2/72 now U.S. Pat. No. 3,809,098, discloses hair curling processes employing monopersulfates and certain chelating agents.
It is an object of the present invention to provide a method for deforming keratin fibers, especially human hair, by means of monopersulfate oxidizing agents without substantial hair bleaching.
It is a further object herein to provide a method for curling hair by means of monopersulfate oxidants. These and other objects are obtained herein as will be seen by the following disclosure.